Paper Conference

Proceedings of ASim Conference 2012: 1st Asia conference of IBPSA-China, Japan, Korea


Statistical analysis of occupancy behavior in open office spaces using measured lighting switch data

Wen-Kuei Chang, Tianzhen Hong

Abstract: Discrepancies between the actual measured building energy consumption and simulated results from computer based building energy modeling programs (BEMPs) can be attributed to many factors. One of the most important factors is occupancy behavior in buildings. Occupancy behavior has significant impact on energy use and operational controls of buildings and their energy service systems as they are designed and operated to provide comfort and healthy working environment for occupants. This study used statistical methods to analyse occupancy data measured in five-minute interval for each open-plan office space (cubicle) located on three floors of an office building. Five typical occupancy patterns were identified based on the average daily 24-hour profiles of an occupant’s presence in a cubicle, which include one-square curve, one-valley curve, two-valley curve, variable curve, and flat curve. The average occupancy profile together with the probability distributions of duration and number of times an occupant absent from his cubicle are key parameters that define the occupancy model. The statistical results also reveal that the number of an occupant absent from his cubicle decreases with the total daily working hours, and the duration of absence from cubicle decreases with the frequency. Furthermore, the occupancy patterns are slightly influenced by the location of cubicles in the building – occupants close to windows or isolated corners tend to leave office less often. The developed occupancy model captures the stochastic nature of occupants moving in and out of cubicles and thus can be used to predict more realistic occupancy schedule which is crucial to improve the accuracy of evaluating energy saving potentials of occupancy based technologies and controls using building simulations.
Pages: 347 - 354